1. Field of the Invention
The present invention relates to a wood drill bit which makes a hole by removing a core or plug of wood.
2. Related Art
In wood frame construction the common method of making a hole for a 3" or 4" vent, drain, conduit or fire protection piping is to drill a series of small holes and saw between these holes to remove a center plug. This is very time consuming and leaves an irregular hole which may not fit the pipe which is to be installed through it. Caulking to fill around the pipe to prevent passage of flame and hot gases with fire-rated fillers is expensive and is required by building codes.
Drill bits commercially available for 3" and 4" pipe that are capable of depths of 3" or more remove 100% of the wood as the bore progresses. This is a maximum effort for the drill motor and the workman. If an obstruction such as a nail is encountered within the diameter of the hole the bit may seize up. The resulting torque may cause injury to the operator and/or the equipment.
Another device which has been used for making larger bore holes is the holesaw, which is a cup-shaped saw fitted onto a mandrel with a twist drill center. These saws are useful for drilling holes in thinner materials such as doors up to about two inches thick. The saws tend to bind with thicker materials and are not available for cuts above about two inches.